Journal of Geophysical Research: Space Physics最新文献

{"title":"Comparison of Cassini Observations and the JPL SATRAD Model for Determining the Energetic Particle Radiation Environment for Enceladus Missions","authors":"A. Andersen,&nbsp;P. Kollmann,&nbsp;J. M. Ratliff","doi":"10.1029/2024JA033442","DOIUrl":"https://doi.org/10.1029/2024JA033442","url":null,"abstract":"<p>Future missions to Saturn's moon Enceladus will be subjected to a significant trapped radiation environment. The Jet Propulsion Laboratory (JPL) Saturn Radiation (SATRAD) model was developed to estimate the Saturn trapped radiation environment for the Cassini mission. This study compares the long-term averaged electron and proton Cassini data to the predictions of the SATRAD model. High-energy electron data, especially that near Enceladus, agree well with SATRAD, suggesting that SATRAD is useful for providing estimates of the radiation environment for future Enceladus missions. Nevertheless, there are many regions where the data and the model do not agree, demonstrating the need to update the SATRAD model using Cassini data.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143622293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Latitudinal Distribution of Thermospheric Nitric Oxide (NO) Infrared Radiative Cooling During May and October 2024 Geomagnetic Storms","authors":"Alok Kumar Ranjan,&nbsp;Duggirala Pallamraju","doi":"10.1029/2024JA033559","DOIUrl":"https://doi.org/10.1029/2024JA033559","url":null,"abstract":"<p>Nitric oxide (NO) radiative cooling, seen as infrared emissions, plays an important role in the energy budget of thermosphere during geomagnetic storms. These emissions serve as a significant heat sink for the thermosphere and facilitate its recovery from the enhanced density and kinetic energy caused by increased Joule heating. Hence, the knowledge of latitudinal distribution of these emissions becomes significant considering the importance of the recovery time duration of the global thermosphere as a consequence of geomagnetic storms. This study discusses the dominating role of storm induced meridional winds, generated due to the Joule heating in the polar regions, in controlling the latitudinal distribution of NO infrared radiative cooling emissions during the two most severe geomagnetic storms of the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>25</mn>\u0000 <mrow>\u0000 <mi>t</mi>\u0000 <mi>h</mi>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $25mathrm{t}mathrm{h}$</annotation>\u0000 </semantics></math> solar cycle (10–11 May, and 10–11 October 2024). During the May 11 event, the peak NO infrared radiative cooling events shifted from the high-latitudes (30–83 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>N) to low-latitude (10 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>S–30 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>N) regions, whereas for the October 11 event, most of the emissions were located in 30–83 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>N, and 0–52 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>S latitude regions. The roles of background seasonal winds, and their associated compositional changes, and the solar energetic radiation (Extreme Ultraviolet <i>or</i> EUV) in modulating the latitudinal variations in the thermospheric NO infrared radiative cooling during both these events, and their consequences for space weather studies are presented.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143622515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Sudden Stratospheric Warming on the Light H and O Species in the Upper Thermosphere","authors":"Changan Wan,&nbsp;Jianqi Qin,&nbsp;Larry J. Paxton","doi":"10.1029/2024JA033243","DOIUrl":"https://doi.org/10.1029/2024JA033243","url":null,"abstract":"<p>Sudden stratospheric warming (SSW) is a significant type of meteorological disturbance that occurs in the winter polar atmosphere. Previous studies have shown that rapid warming of the polar stratosphere can induce electrodynamic and thermodynamic variabilities in the upper atmosphere over the entire globe. However, the effects of SSW on the light neutral species (e.g., H and O) remain poorly understood. Here we report coincident H and O variations in the upper thermosphere during SSW events, based on observations from the Global Ultraviolet Imager (GUVI) on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission. The GUVI observations indicate rapid increase of the H abundance and reduction of the O abundance at low latitudes within <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>30</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${sim} 30{}^{circ}$</annotation>\u0000 </semantics></math>S–30<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>N in the upper thermosphere (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>200–500 km) following the onset of an Antarctic and an Arctic SSW event that occurred under high solar condition in September 2002 and January 2003, respectively. Moreover, we found that the effects of SSW on the H variations are barely discernible from the GUVI observations that were acquired in 2004–2006 under relatively low solar condition. We used the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCM-X) to simulate the effects of SSW on the H and O abundance. The modeling results under both high and low solar conditions are consistent with the GUVI observations, indicating that solar activity modulates the effects of SSW on vertical coupling between the lower and upper atmosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143622294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Are Supersubstorms Substorms? Extreme Nightside Auroral Electrojet Activities During the May 2024 Geomagnetic Storm","authors":"Ying Zou,&nbsp;Ohtani Shin,&nbsp;Jesper W. Gjerloev,&nbsp;Brian J. Anderson,&nbsp;Colin L. Waters,&nbsp;Chih-Ping Wang,&nbsp;Jun Liang,&nbsp;Larry L. Lyons,&nbsp;Asti Bhatt","doi":"10.1029/2024JA033303","DOIUrl":"https://doi.org/10.1029/2024JA033303","url":null,"abstract":"<p>Enhancement of currents in Earth's ionosphere adversely impacts systems and technologies, and one example of extreme enhancement is supersubstorms. Despite the name, whether a supersubstorm is a substorm remains an open question, because studies suggest that unlike substorms, supersubstorms sometimes affect all local times including the dayside. The spectacular May 2024 storm contains signatures of two supersubstorms that occurred successively in time with similar magnitude and duration, and we explore the nature of them by examining the morphology of the auroral electrojet, the corresponding disturbances in the magnetosphere, and the solar wind driving conditions. The results show that the two events exhibit distinctly different features. The first event was characterized by a locally intensified electrojet followed by a rapid expansion in latitude and local time. Auroral observations showed poleward expansion of auroras (or aurorae), and geosynchronous observations showed thickening of the plasma sheet, magnetic field dipolarization, and energetic particle injections. The second event was characterized by an instantaneous intensification of the electrojet over broad latitude and local time. Auroras did not expand but brightened simultaneously across the sky. Radar and LEO observations showed enhancement of the ionospheric electric field. Therefore, the first event is a substorm, whereas the second event is enhancement of general magnetospheric convection driven by a solar wind pressure increase. These results illustrate that the so-called supersubstorms have more than one type of driver, and that internal instability in the magnetotail and external driving of the solar wind are equally important in driving extreme auroral electrojet activity.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology of Twisted Flux Ropes and Plasma Motions in a Prominence-Cavity System Observed From Two Opposite Viewpoints","authors":"P. T. Jain Jacob,&nbsp;Ram Ajor Maurya","doi":"10.1029/2024JA033479","DOIUrl":"https://doi.org/10.1029/2024JA033479","url":null,"abstract":"<p>We investigate the three-dimensional structures of a prominence-cavity system from two distinct vantage points. For this purpose, we have used the observations recorded by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and the Extreme Ultraviolet Imager (EUVI) on board the Solar Terrestrial Relations Observatory - Ahead (STEREO-A). Our analysis reveals that the prominence-cavity system was formed by the emergence of two oppositely rotating magnetic structures from the photosphere. The cavity, identified as an intensity-depleted region located above the prominence, was surrounded by horn-like structures. These prominence-horns, observed by both observatories, unveiled the presence of twisted flux ropes within the cavity. As the system evolved, we observed the prominence horns undergoing repeated upward motion accompanied by multiple instances of downward plasma motions. These observations suggest the occurrence of magnetic reconnection processes within the prominence-cavity system. We tracked the dynamics of these plasma motions in details, estimating their average speeds, physical parameters including the temperature, magnetic field, and the plasma density. In its final stage, the structure exhibited positive helicity, with left-bearing barbs that reflected the twisted flux rope morphology of the prominence. Our findings indicate that the prominence-cavity system was non-eruptive due to the presence of oppositely directed twist and writhe, which helped to conserve it's helicity.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Properties of EMIC Waves and EMIC Wave-Driven Electron Precipitation in Subauroral Latitudes Observed at Athabasca, Canada","authors":"Asuka Hirai,&nbsp;Fuminori Tsuchiya,&nbsp;Takahiro Obara,&nbsp;Yoshizumi Miyoshi,&nbsp;Yuto Katoh,&nbsp;Yasumasa Kasaba,&nbsp;Kazuo Shiokawa,&nbsp;Atsushi Kumamoto,&nbsp;Yoshiya Kasahara,&nbsp;Shoya Matsuda,&nbsp;Hiroaki Misawa,&nbsp;Satoshi Kurita,&nbsp;Chae-Woo Jun,&nbsp;Hiroyo Ohya,&nbsp;Martin G. Connors","doi":"10.1029/2024JA033357","DOIUrl":"https://doi.org/10.1029/2024JA033357","url":null,"abstract":"<p>Electromagnetic ion cyclotron (EMIC) waves are believed to cause the loss of relativistic electrons from the outer radiation belt into the atmosphere due to pitch angle scattering. However, it is still unclear whether all EMIC waves can scatter relativistic electrons or which conditions are favorable for pitch angle scattering by EMIC waves. In this study, we performed a 2-year data analysis of EMIC waves and EMIC wave-driven electron precipitation (EP), from 1 November 2016–31 October 2018. Electromagnetic ion cyclotron waves were observed using a ground-based magnetometer installed at Athabasca (ATH, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>=</mo>\u0000 </mrow>\u0000 <annotation> $L=$</annotation>\u0000 </semantics></math>4.3), Canada. Electron precipitation events were identified from very low-frequency radio waves propagated from the transmitters at North Dakota (NDK, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>=</mo>\u0000 </mrow>\u0000 <annotation> $L=$</annotation>\u0000 </semantics></math>3.0) and Seattle (NLK, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>=</mo>\u0000 </mrow>\u0000 <annotation> $L=$</annotation>\u0000 </semantics></math>2.9) stations in USA to the receiver installed at ATH. The magnetic local time dependence of EMIC waves showed higher occurrence rates in the dawn sector. In contrast, EMIC waves accompanied by EP were localized in the dusk sector and were likely to occur during geomagnetic substorms. We found that EMIC waves accompanied by EP were associated with the main phase of geomagnetic storms and occurred inside the plasmapause. These results suggest that the EMIC waves that cause EP occur in the overlap region between the ring current and dense cold plasma during the main phase of geomagnetic storms. This is consistent with previous studies describing that the electron resonant energy with EMIC waves is lower in regions with high plasma density.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033357","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sub-MeV Electron Precipitation Driven by EMIC Waves in Plasmaspheric Plumes at High L Shells","authors":"Murong Qin,&nbsp;Wen Li,&nbsp;Yukitoshi Nishimura,&nbsp;Sheng Huang,&nbsp;Qianli Ma,&nbsp;Miroslav Hanzelka,&nbsp;Luisa Capannolo,&nbsp;Xiao-Chen Shen,&nbsp;Vassilis Angelopoulos,&nbsp;Xin An,&nbsp;Anton V. Artemyev,&nbsp;Longzhi Gan","doi":"10.1029/2025JA033756","DOIUrl":"https://doi.org/10.1029/2025JA033756","url":null,"abstract":"<p>Electromagnetic ion cyclotron (EMIC) waves are known to be efficient for precipitating &gt;1 MeV electrons from the magnetosphere into the upper atmosphere. Despite considerable evidence showing that EMIC-driven electron precipitation can extend down to sub-MeV energies, the precise physical mechanism driving sub-MeV electron precipitation remains an active area of investigation. In this study, we present an electron precipitation event observed by ELFIN CubeSats on 11 January 2022, exclusively at sub-MeV energy at <i>L</i> ∼ 8–10.5, where trapped MeV electrons were nearly absent. The THEMIS satellites observed conjugate H-band and He-band EMIC waves and hiss waves in plasmaspheric plumes near the magnetic equator. Quasi-linear diffusion results demonstrate that the observed He-band EMIC waves, with a high ratio of plasma to electron cyclotron frequency, can drive electron precipitation down to ∼400 keV. Our findings suggest that exclusive sub-MeV precipitation (without concurrent MeV precipitation) can be associated with EMIC waves, especially in the plume region at high <i>L</i> shells.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ion Moment Variability Across Substorm Phases: Statistical Insights","authors":"Sanjay Kumar,&nbsp;Tuija I. Pulkkinen,&nbsp;T. Pitkänen","doi":"10.1029/2024JA032953","DOIUrl":"https://doi.org/10.1029/2024JA032953","url":null,"abstract":"&lt;p&gt;In this study, we analyze 5 years of THEMIS and MMS mission data to statistically investigate the distribution of earthward and tailward ion flows during three substorm phases in Earth's magnetotail plasma sheet. The average flow patterns reveal primarily slow sunward and occasional fast tailward convection throughout all substorm phases. Most earthward flows in the plasma sheet had speeds around 35 km/s within the region &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;15&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $X &gt; -15 {R}_{E}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, as observed by THEMIS, while peak velocities reached up to 350 km/s in areas where &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mo&gt;&lt;&lt;/mo&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;15&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $X&lt; -15 {R}_{E}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, as observed by MMS-1. Tailward flows showed velocities near 30 km/s earthward of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mo&gt;≈&lt;/mo&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;15&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $Xapprox -15$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, according to THEMIS, with peak velocities of 300 km/s in the region &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;15&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $X &gt; -15 {R}_{E}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, based on MMS-1 data. Dusk-dawn &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;V&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;⊥&lt;/mo&gt;\u0000 &lt;mi&gt;y&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({V}_{perp y}right)$&lt;/annotation&gt;\u0000 ","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032953","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radial Diffusion Driven by Spatially Localized ULF Waves in the Earth's Magnetosphere","authors":"Adnane Osmane,&nbsp;Jasmine K. Sandhu,&nbsp;Tom Elsden,&nbsp;Oliver Allanson,&nbsp;Lucile Turc","doi":"10.1029/2024JA033393","DOIUrl":"https://doi.org/10.1029/2024JA033393","url":null,"abstract":"<p>Ultra-Low Frequency (ULF) waves are critical drivers of particle acceleration and loss in the Earth's magnetosphere. While statistical models of ULF-induced radial transport have traditionally assumed that the waves are uniformly distributed across magnetic local time (MLT), decades of observational evidence show significant MLT localization of ULF waves in the Earth's magnetosphere. This study presents, for the first time, a quasi-linear radial diffusion coefficient accounting for localized ULF waves. Our results reveal that when ULF waves cover more than 30% of the MLT, the radial diffusion efficiency is comparable to that of uniform wave distributions. However, when ULF waves are confined within 10% of the drift orbit, the transport coefficient is enhanced by 10%–25%, indicating that narrowly localized ULF waves are efficient drivers of radial diffusion.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetospheric Cold Plasma Diagnostics Using High Altitude GNSS Signals","authors":"D. M. Malaspina,&nbsp;P. Axelrad,&nbsp;J. Goldstein,&nbsp;R. Nikoukar,&nbsp;D. Rowland,&nbsp;S. Fantinato,&nbsp;E. Miotti","doi":"10.1029/2024JA033426","DOIUrl":"https://doi.org/10.1029/2024JA033426","url":null,"abstract":"<p>The plasmasphere is a key component of Earth's magnetosphere, regulating numerous energy transfer processes. The plasmasphere is also a cold multi-species plasma. Tracing differences in dynamics between low and high mass cold ions is important for identifying the processes that drive plasmaspheric evolution. At the same time, measurements of cold ion fractional composition within the plasmasphere are sparse and challenging to obtain. Seeking to overcome this challenge, this work presents a novel concept for combining extreme ultraviolet (EUV) photon imaging and Global Navigation Satellite System (GNSS) pseudorange observations to measure cold ion fractional composition throughout the plasmasphere. The feasibility of this concept is demonstrated using a model plasmaspheric density structure combined with known properties of GNSS transmitters and signals. Implementation of this measurement concept on a future space mission has the potential to enable significant new progress understanding processes that drive plasmaspheric and, extension magnetospheric dynamics.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033426","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}